Sentinel lymph node biopsy status is not the most powerful predictor of prognosis in cutaneous melanoma.

Sentinel lymph node (SLN) status has been advocated in several recently published articles as the single most valuable prognostic marker for melanoma, and of greater prognostic importance than more established parameters such as Breslow thickness. A careful examination of the evidence for these claims, however, indicates that they are not substantiated by the available data, are somewhat misleading and suggest misinterpretation of the statistical analysis of the papers to which they refer. We will examine the basis for these claims and show why they are invalid.

Mesorhizobium calcicola sp. nov., Mesorhizobium waitakense sp. nov., Mesorhizobium sophorae sp. nov., Mesorhizobium newzealandense sp. nov. and Mesorhizobium kowhaii sp. nov. isolated from Sophora root nodules.

In total, 31 strains of Gram-stain-negative, rod-shaped bacteria were isolated from Sophora root nodules and authenticated as rhizobia on this host. Based on 16S rRNA gene phylogeny, they were shown to belong to the genus Mesorhizobium, with the representative strains ICMP 19560T, ICMP 19523T, ICMP 19535T, ICMP 19545T and ICMP 19512T being related most closely to Mesorhizobium sangaii SCAU7T (99.9-99.6 % similarity), Mesorhizobium cantuariense ICMP 19515T (99.7-99.6 %) and Mesorhizobium ciceri UMP-CA7T (99.7-99.5 %). Additionally, the novel strains formed distinct groups based on housekeeping gene sequence analysis and were closely related to Mesorhizobium waimense ICMP 19557T (93.5-94.9, 92.5-95.6 and 94.2-96.0 %), M. cantuariense ICMP 19515T (93.1-97.7, 93.5-95.4 and 94.8-96.8 %) and M. ciceri UMP-CA7T (93.2-97.2, 94.6-96.8 and 95.5-97.3 %) for glnII, recA and rpoB, respectively. Chemotaxonomic data supported the assignment of the strains to the genus Mesorhizobium, and DNA-DNA hybridizations, matrix-assisted laser desorption/ionization time-of-flight MS analysis, enterobacterial repetitive intergenic consensus PCR, physiological and biochemical tests allowed the genotypic and phenotypic differentiation from their nearest neighbouring species. Therefore, these strains represent five novel species for which the names Mesorhizobium calcicola sp. nov. (type strain ICMP 19560T = LMG 28224T = HAMBI 3609T), Mesorhizobium waitakense sp. nov. (type strain ICMP 19523T = LMG 28227T = HAMBI 3605T), Mesorhizobium sophorae sp. nov. (type strain ICMP 19535T = LMG 28223T = HAMBI 3606T), Mesorhizobium newzealandense sp. nov. (type strain ICMP 19545T = LMG 28226T = HAMBI 3607T) and Mesorhizobium kowhaii sp. nov. (type strain ICMP 19512T = LMG 28222T = HAMBI 3603T) are proposed.

When do plant radiations influence community assembly? The importance of historical contingency in the race for niche space.

Plant radiations are widespread but their influence on community assembly has rarely been investigated. Theory and some evidence suggest that radiations can allow lineages to monopolize niche space when founding species arrive early into new bioclimatic regions and exploit ecological opportunities. These early radiations may subsequently reduce niche availability and dampen diversification of later arrivals. We tested this hypothesis of time-dependent lineage diversification and community dominance using the alpine flora of New Zealand. We estimated ages of 16 genera from published phylogenies and determined their relative occurrence across climatic and physical gradients in the alpine zone. We used these data to reconstruct occupancy of environmental space through time, integrating palaeoclimatic and palaeogeological changes. Our analysis suggested that earlier-colonizing lineages encountered a greater availability of environmental space, which promoted greater species diversity and occupancy of niche space. Genera that occupied broader niches were subsequently more dominant in local communities. An earlier time of arrival also contributed to greater diversity independently of its influence in accessing niche space. We suggest that plant radiations influence community assembly when they arise early in the occupancy of environmental space, allowing them to exclude later-arriving colonists from ecological communities by niche preemption.

Species radiation by niche shifts in New Zealand's rockcresses (Pachycladon, Brassicaceae).

Adaptive radiations such as the Darwin finches in the Galapagos or the cichlid fishes from the Eastern African Great Lakes have been a constant source of inspiration for biologists and a stimulus for evolutionary thinking. A central concept behind adaptive radiation is that of evolution by niche shifts, or ecological speciation. Evidence for adaptive radiations generally requires a strong correlation between phenotypic traits and the environment. But adaptive traits are often cryptic, hence making this phenotype-environment approach difficult to implement. Here we propose a procedure for detecting adaptive radiation that focuses on species' ecological niche comparisons. It evaluates whether past ecological disparity in a group fits better a neutral Brownian motion model of ecological divergence or a niche shift model. We have evaluated this approach on New Zealand rockcresses (Pachycladon) that recently radiated in the New Zealand Alps. We show that the pattern of ecological divergence rejects the neutral model and is consistent with that of a niche shift model. Our approach to detect adaptive radiation has the advantage over alternative approaches that it focuses on ecological niches, a key concept behind adaptive radiation. It also provides a way to evaluate the importance of ecological speciation in adaptive radiations and will have general application in evolutionary studies. In the case of Pachycladon, the high estimated diversification rate, the distinctive ecological niches of species, and the evidence for ecological speciation suggest a remarkable example of adaptive radiation.

Mesorhizobium waimense sp. nov. isolated from Sophora longicarinata root nodules and Mesorhizobium cantuariense sp. nov. isolated from Sophora microphylla root nodules.

In total 14 strains of Gram-stain-negative, rod-shaped bacteria were isolated from Sophora longicarinata and Sophora microphylla root nodules and authenticated as rhizobia on these hosts. Based on the 16S rRNA gene phylogeny, they were shown to belong to the genus Mesorhizobium, and the strains from S. longicarinata were most closely related to Mesorhizobium amorphae ACCC 19665T (99.8­99.9 %), Mesorhizobium huakuii IAM 14158T (99.8­99.9 %), Mesorhizobium loti USDA 3471T (99.5­99.9 %) and Mesorhizobium septentrionale SDW 014T (99.6­99.8 %), whilst the strains from S. microphylla were most closely related to Mesorhizobium ciceri UPM-Ca7T (99.8­99.9 %), Mesorhizobium qingshengii CCBAU 33460T (99.7 %) and Mesorhizobium shangrilense CCBAU 65327T (99.6 %). Additionally, these strains formed two distinct groups in phylogenetic trees of the housekeeping genes glnII, recA and rpoB. Chemotaxonomic data, including fatty acid profiles, supported the assignment of the strains to the genus Mesorhizobium and allowed differentiation from the closest neighbours. Results of DNA­DNA hybridizations, MALDI-TOF MS analysis, ERIC-PCR, and physiological and biochemical tests allowed genotypic and phenotypic differentiation of our strains from their closest neighbouring species. Therefore, the strains isolated from S. longicarinata and S. microphylla represent two novel species for which the names Mesorhizobium waimense sp. nov. (ICMP 19557T = LMG 28228T = HAMBI 3608T) and Mesorhizobium cantuariense sp. nov. (ICMP 19515T = LMG 28225T = HAMBI 3604T), are proposed respectively.

Chemosystematic analyses of Gingidia volatiles.

The leave volatiles of six Gingidia species from New Zealand and Australia and the seed volatiles of G. grisea were characterized by solid-phase microextraction (SPME)-GC/MS analysis. This technique, using a small quantity of samples and automated extraction, gave repeatable results, with maximum sensitivity for medium volatility compounds. The major monoterpenes among the volatiles, i.e., ß-phellandrene (4), limonene (6), and γ-terpinene (5), and phenylpropanoids, i.e., estragole (3), (E)-anethole (7), and myristicin (1), showed to be useful chemotaxonomic markers. For G. grisea leaves and seeds, similar compositions were detected, characterized by high contents of 4. As leaves were more readily available for study than seeds, they were used for further investigations. The G. grisea leaf volatiles showed infraspecific variation in the ratio of 4/5 between and within sites of collection. The G. montana leaf volatiles also showed infraspecific variation, with high contents of 3 at one site and high contents of 7 at another. The SPME-GC/MS analysis of G. montana herbarium voucher specimens resulted in the identification of further chemotypes for this species. The volatiles of the G. amphistoma samples were all dominated by 7 and those of the G. haematitica samples were rich in 5. Moreover, single plants of two Australian Gingidia species were analyzed; the volatiles of G. harveyana showed high concentrations of 5 and 7, whereas those of G. rupicola were dominated by 5 and 1.

High frequency of BRAF mutations in nevi.

To evaluate the timing of mutations in BRAF (v-raf murine sarcoma viral oncogene homolog B1) during melanocytic neoplasia, we carried out mutation analysis on microdissected melanoma and nevi samples. We observed mutations resulting in the V599E amino-acid substitution in 41 of 60 (68%) melanoma metastases, 4 of 5 (80%) primary melanomas and, unexpectedly, in 63 of 77 (82%) nevi. These data suggest that mutational activation of the RAS/RAF/MAPK pathway in nevi is a critical step in the initiation of melanocytic neoplasia but alone is insufficient for melanoma tumorigenesis.

Global Brassicaceae phylogeny based on filtering of 1,000-gene dataset.

The mustard family (Brassicaceae) is a scientifically and economically important family, containing the model plant Arabidopsis thaliana and numerous crop species that feed billions worldwide. Despite its relevance, most phylogenetic trees of the family are incompletely sampled and often contain poorly supported branches. Here, we present the most complete Brassicaceae genus-level family phylogenies to date (Brassicaceae Tree of Life or BrassiToL) based on nuclear (1,081 genes, 319 of the 349 genera; 57 of the 58 tribes) and plastome (60 genes, 265 genera; all tribes) data. We found cytonuclear discordance between the two, which is likely a result of rampant hybridization among closely and more distantly related lineages. To evaluate the impact of such hybridization on the nuclear phylogeny reconstruction, we performed five different gene sampling routines, which increasingly removed putatively paralog genes. Our cleaned subset of 297 genes revealed high support for the tribes, whereas support for the main lineages (supertribes) was moderate. Calibration based on the 20 most clock-like nuclear genes suggests a late Eocene to late Oligocene origin of the family. Finally, our results strongly support a recently published new family classification, dividing the family into two subfamilies (one with five supertribes), together representing 58 tribes. This includes five recently described or re-established tribes, including Arabidopsideae, a monogeneric tribe accommodating Arabidopsis without any close relatives. With a worldwide community of thousands of researchers working on Brassicaceae and its diverse members, our new genus-level family phylogeny will be an indispensable tool for studies on biodiversity and plant biology.

Plant radiation history affects community assembly: evidence from the New Zealand alpine.

The hypothesis that early plant radiations on islands dampen diversification and reduce habitat occupancy of later radiations via niche pre-emption has never, to our knowledge, been tested. We investigated clade-level dynamics in plant radiations in the alpine zone, New Zealand. Our aim was to determine whether radiations from older colonizations influenced diversification and community dominance of species from later colonizations within a common bioclimatic zone over the past ca 10 Myr. We used stem ages derived from the phylogenies of 17 genera represented in alpine plant communities in the Murchison Mountains, Fiordland, and assessed their presence and cover in 262 (5 × 5 m) vegetation plots. Our results show clear age-related community assembly effects, whereby congenerics from older colonizing genera co-occur more frequently and with greater cover per unit area than those from younger colonizing genera. However, we find no evidence of increased species richness with age of colonization in the alpine zone. The data support priority effects via niche pre-emption among plant radiations influencing community assembly.

Island species radiation and karyotypic stasis in Pachycladon allopolyploids.

BACKGROUND: Pachycladon (Brassicaceae, tribe Camelineae) is a monophyletic genus of ten morphologically and ecogeographically differentiated, and presumably allopolyploid species occurring in the South Island of New Zealand and in Tasmania. All Pachycladon species possess ten chromosome pairs (2n = 20). The feasibility of comparative chromosome painting (CCP) in crucifer species allows the origin and genome evolution in this genus to be elucidated. We focus on the origin and genome evolution of Pachycladon as well as on its genomic relationship to other crucifer species, particularly to the allopolyploid Australian Camelineae taxa. As species radiation on islands is usually characterized by chromosomal stasis, i.e. uniformity of chromosome numbers/ploidy levels, the role of major karyotypic reshuffling during the island adaptive and species radiation in Pachycladon is investigated through whole-genome CCP analysis. RESULTS: The four analyzed Pachycladon species possess an identical karyotype structure. The consensual ancestral karyotype is most likely common to all Pachycladon species and corroborates the monophyletic origin of the genus evidenced by previous phylogenetic analyses. The ancestral Pachycladon karyotype (n = 10) originated through an allopolyploidization event between two genomes structurally resembling the Ancestral Crucifer Karyotype (ACK, n = 8). The primary allopolyploid (apparently with n = 16) has undergone genome reshuffling by descending dysploidy toward n = 10. Chromosome "fusions" were mediated by inversions, translocations and centromere inactivation/loss. Pachycladon chromosome 3 (PC3) resulted from insertional fusion, described in grasses. The allopolyploid ancestor originated in Australia, from the same or closely related ACK-like parental species as the Australian Camelineae allopolyploids. However, the two whole-genome duplication (WGD) events were independent, with the Pachycladon WGD being significantly younger. The long-distance dispersal of the diploidized Pachycladon ancestor to New Zealand was followed by the Pleistocene species radiation in alpine habitats and characterized by karyotypic stasis. CONCLUSIONS: Karyotypic stasis in Pachycladon suggests that the insular species radiation in this genus proceeded through homoploid divergence rather than through species-specific gross chromosomal repatterning. The ancestral Pachycladon genome originated in Australia through an allopolyploidization event involving two closely related parental genomes, and spread to New Zealand by a long-distance dispersal. We argue that the chromosome number decrease mediated by inter-genomic reshuffling (diploidization) could provide the Pachycladon allopolyploid founder with an adaptive advantage to colonize montane/alpine habitats. The ancestral Pachycladon karyotype remained stable during the Pleistocene adaptive radiation into ten different species.

Transcript and protein profiling identify candidate gene sets of potential adaptive significance in New Zealand Pachycladon.

BACKGROUND: Transcript profiling of closely related species provides a means for identifying genes potentially important in species diversification. However, the predictive value of transcript profiling for inferring downstream-physiological processes has been unclear. In the present study we use shotgun proteomics to validate inferences from microarray studies regarding physiological differences in three Pachycladon species. We compare transcript and protein profiling and evaluate their predictive value for inferring glucosinolate chemotypes characteristic of these species. RESULTS: Evidence from heterologous microarrays and shotgun proteomics revealed differential expression of genes involved in glucosinolate hydrolysis (myrosinase-associated proteins) and biosynthesis (methylthioalkylmalate isomerase and dehydrogenase), the interconversion of carbon dioxide and bicarbonate (carbonic anhydrases), water use efficiency (ascorbate peroxidase, 2 cys peroxiredoxin, 20 kDa chloroplastic chaperonin, mitochondrial succinyl CoA ligase) and others (glutathione-S-transferase, serine racemase, vegetative storage proteins, genes related to translation and photosynthesis). Differences in glucosinolate hydrolysis products were directly confirmed. Overall, prediction of protein abundances from transcript profiles was stronger than prediction of transcript abundance from protein profiles. Protein profiles also proved to be more accurate predictors of glucosinolate profiles than transcript profiles. The similarity of species profiles for both transcripts and proteins reflected previously inferred phylogenetic relationships while glucosinolate chemotypes did not. CONCLUSIONS: We have used transcript and protein profiling to predict physiological processes that evolved differently during diversification of three Pachycladon species. This approach has also identified candidate genes potentially important in adaptation, which are now the focus of ongoing study. Our results indicate that protein profiling provides a valuable tool for validating transcript profiles in studies of adaptive divergence.

Atypical fibroxanthoma: a histological and immunohistochemical review of 171 cases.

The clinical and histological features of 171 atypical fibroxanthomas (AFX) from a single institution in Western Australia are outlined. This area experiences high levels of solar radiation, and all assessable biopsies showed solar elastosis. Patients were aged between 41 and 97 years (median age 74), with 76% of tumors occurring in men (male to female ratio approximately 3 to 1). Most tumors were small, with a median diameter of 10 mm and a range of 4-35 mm. Only 5% exceeded 20 mm in diameter. Most AFX were well-circumscribed dermal lesions, with limited invasion of subcutis in a minority. Histological variants identified included keloidal (n = 8), clear cell (n = 3), and granular cell (n = 3), plaque like (n = 4), and myxoid (n = 1). Bland cytological appearances (spindle cell nonpleomorphic AFX) were noted in 5 tumors, with osteoclast-like giant cells in 2. Features suggesting regression were present in 22 cases. Two cases recurred locally, none metastasized. No tumors expressed melanocytic or epithelial markers. Seventy-four percent of cases expressed smooth muscle actin, typically strongly and diffusely. No AFX stained with desmin. Only 1 of 50 cases was CD117 positive. In conclusion, AFX may show a wide range of histological appearances, and a panel of immunohistochemical markers is essential to make the correct diagnosis. Histological mimics, such as poorly differentiated squamous cell carcinoma, must be carefully excluded. Specific diagnosis is important because there seems to be a very low risk of recurrence or metastasis despite the frequently alarming histology.

A Pleistocene inter-tribal allopolyploidization event precedes the species radiation of Pachycladon (Brassicaceae) in New Zealand.

The Southern Alps in New Zealand contain many herbaceous plant groups that have radiated during the Plicoene-Pleistocene. The species in these genera tend to be polyploid relative to their overseas close relatives, an observation of much interest given that hybridization and allopolyploidy have recently been suggested as a possible stimulus for adaptive radiation. We were interested to determine whether or not allopollyploidy was a feature of Pachycladon, a genus which is hypothesised to have adaptively diversified onto different geological substrates in the mountains of the South Island of New Zealand. Phylogenetic analyses of five single-copy nuclear genes show that Pachycladon species have two copies of each gene representing two highly diverged evolutionary lineages from the Brassicaceae. Molecular clock analyses of all loci suggest that the two genome copies in Pachycladon diverged 8 million years ago, and that the allopolyploid origin of the genus occurred during the Pleistocene between 1.6 and 0.8 million years ago. This hybridization event at the origin of the Pachycladon radiation is perhaps the most extreme example yet reported of successful hybridization between distantly related parents.

Degos' disease with delayed involvement of the gastrointestinal tract.

A 75-year-old woman presented with pink papules over the trunk and limbs. Over the next few weeks, the papules became umbilicated and then developed into porcelain-white lesions with a rose or violaceous rim. A biopsy of one of these lesions revealed superficial and deep dermal lymphohistiocytic inflammation, mainly perivascular with a central zone of infarction consistent with Degos' disease. Three years later, she presented with increasing abdominal pain, anaemia, raised inflammatory markers and an abdominal bruit. Angiography showed splanchnic vessel stenosis possibly secondary to vasculitis and she underwent successful balloon dilatation. Treatment with prednisolone was commenced. There has been no recurrence of lesions in the 12 months since the balloon dilatation.

Genetic Variation and Hybridisation among Eight Species of kowhai (Sophora: Fabaceae) from New Zealand Revealed by Microsatellite Markers.

We analysed nine microsatellite markers for 626 individuals representing the geographic range of eight closely related endemic New Zealand species of Sophora. Structure analysis identified the optimal K value as seven, with samples identified as Sophorachathamica, Sophorafulvida, Sophoralongicarinata, and Sophoraprostrata retrieved as well-defined groups. The remaining samples formed less resolved groups referable to Sophoratetraptera and Sophoragodleyi, with Sophoramicrophylla and Sophoramolloyi forming the seventh group. Our data suggest that considerable admixture occurs and this is most likely the result of hybridisation or introgression. S.fulvida shows admixture with the sympatric S.chathamica, and the widespread S.microphylla exhibits admixture with the sympatric S.godleyi, S.molloyi, and S.tetraptera.

Basal Cell Carcinoma Arises from Interfollicular Layer of Epidermis.

BACKGROUND: BCC is currently the most common type of skin cancer in humans. Although having a low-grade malignancy and metastatic potential, BCC is locally aggressive and destructive. Despite numerous studies, the origin of BCC, whether arising from the follicular or interfollicular layer, remains controversial. OBJECTIVES: This study aims to evaluate whether BCC arises from the follicular or interfollicular layer by using immunohistochemical staining. METHODS: Twenty-three specimens of superficial and nodular BCC at its very early stage were examined. The samples were immunohistochemically stained using BerEP4 antibody. The stained specimens were then examined and scored by 2 independent observers. RESULTS: BerEP4 was found to be strongly positive in all BCC lesions, including a very early lesions budding off the basal layer of the epidermis. CONCLUSION: This study confirmed that the origin site of BCC is basal layer of epidermis. This finding suggests that BCC arises from the interfollicular epidermis.

Toward the discrimination of early melanoma from common and dysplastic nevus using fiber optic diffuse reflectance spectroscopy.

We describe a study of the discrimination of early melanoma from common and dysplastic nevus using fiber optic diffuse reflectance spectroscopy. Diffuse reflectance spectra in the wavelength range 550 to 1000 nm are obtained using 400-microm core multimode fibers arranged in a six-illumination-around-one-collection geometry with a single fiber-fiber spacing of 470 microm. Spectra are collected at specific locations on 120 pigmented lesions selected by clinicians as possible melanoma, including 64 histopathologically diagnosed as melanoma. These locations are carried through to the histopathological diagnosis, permitting a spatially localized comparison with the corresponding spectrum. The variations in spectra between groups of lesions with different diagnoses are examined and reduced to features suitable for discriminant analysis. A classifier distinguishing between benign and malignant lesions performs with sensitivity/specificity of between 6469% and 7278%. Classifiers between pairs of the group common nevus, dysplastic nevus, in situ melanoma, and invasive melanoma show better or similar performance than the benign/malignant classifier, and analysis provides evidence that different spectral features are needed for each pair of groups. This indicates that multiple discriminant systems are likely to be required to distinguish between melanoma and similar lesions.

A clinicopathologic review of lethal nonmelanoma skin cancers in Western Australia.

BACKGROUND: Nonmelanoma skin cancer (NMSC) comprises a heterogeneous group of cancers. A comprehensive review of NMSC mortality has not been performed previously in this region. OBJECTIVE: We sought to document the population affected by lethal NMSC, the types of tumors involved, and their histopathologic features. METHODS: Death certificates of all patients who died from NMSC were examined. Histology of the primary lesion was reviewed in cases when the primary lesion was identified and sections were available. RESULTS: A total of 120 NMSC deaths occurred, including 89 caused by squamous cell carcinoma, 22 by Merkel cell carcinoma, and 9 others. The median age at death was 79 years, unless the patients were immune deficient (68 years). When the primary lesion was identified (n = 45), the median survival after diagnosis was 17 months; 75% of patients died within 3 years. Lethal neoplasms were deeply invasive and infiltrated into the reticular dermis and beyond. Three squamous cell carcinomas were reclassified as adenosquamous carcinoma. CONCLUSION: Lethal NMSC occurs in the elderly and consists mainly of 3 types of deeply invasive cancers.